Not to derail this thread completely, but it has been established in the TK prop nut community for quite some time now that the "painted vs. unpainted suits" theory stemmed from the fact that Simon's suit has been painted after production wrapped. Painted stormtroopers have since been debunked, even by Brian Muir himself I believe - have to check that again though. J.W. Rinzler's making of book does not mention painting the suits either.
It's a one time thing on Si's suit and was misinterpreted by a whole lot of people. According to the logic of painting what was white plastic to begin with white (time-consuming and not cost-effective), all surviving ABS hero helmets accounted for these days should also be painted to match the painted suits, and not one of those shows even the slightest hint of paint.
Also, if they did paint the suits white, why would they use another shade of white that so clearly contrasts the painted stunt HDPE helmets?
No armor suit was ever painted white, other than maybe after filming ended.
Both of your 2007 LFL archive pics taken by Matt Gauthier for the Ainsworth court case show unpainted ABS suits. The sheen of the ABS is very obvious in both of those archive pics.
Check the upper left (looking at the pic) torso split rivet for the white paint smeared around the rivet head, and over the otherwise unpainted surrounding ABS, it's clearly just painted rivets in unpainted plastic, with a visible difference in the 2 shades of white.
The shin shows what I believe is residue either from being re-glued the wrong way around, or just residue of tape to quickly close the shins (maybe for ESB). The shade of residue is too yellow and it's raised vs recessed, chipped off paint.
Also, paint never chips in such straight, controlled lines like we see on those pics.